Closure and method of making the same



July 24, 1934. J RF JR 1,967,725

CLOSURE AND METHOD OF MAKING- THE SAME Filed Sept. 30, 1951 ATTORNEYS Patented July 24, 1934 UNITED STATES PATENT OFFICE John Rutherford, Jr., Slingerlands, N. Y., asslgnor to The Embossing C ompany, Albany, N. Y., a

corporation of New York Appllcation september 30, 1931, Serial No. 585,951

7 Claim.

This invention relates to closures and, more particularly, to skirted wooden screw caps for bottles and like containers.

Among the objects of this invention is to provide an inexpensive and novel method of making a wooden screw cap having its thread integral therewith. Another object is to produce a wooden cap having a thread cut therefrom which is strong and has a smooth and regular surface. Another object of the invention is to produce from wood a lightly constructed screw cap of the crown and skirt variety and which is sufficiently strong to prevent collapse thereof even though the crown and the skirt are quite thin.

Other and incidental objects will be disclosed hereinafter in the specification and claims and in the drawing in which:--

Fig. 1 shows a blank of wood from which the screw cap is produced.

Fig. 2 illustrates a form into which the blank of Fig. 1 has been compressed.

Fig. 3 shows the blank of Fig. 2 after its center has been removed.

Fig. 4 is va plan of the blank illustrated in Fi 3.

Fig. 5 is a section on line 5--5 of Fig. 4.

Fig. 6 is a section along the axis of the screw cap finished from the shell illustrated in Figs. 3, 4 and 5.

Fig. 7 illustrates an alternative manner of compressing the undeformed blank of Fig. 1.

Fig. 8 shows the blank of Fig. '7 after its center has been removed.

Fig. 9 is a plan of the shell illustrated in Fig. 8.

Fig. 10 is a section on line 10-10 of Fig. 9.

Fig. 11 is a section along the axis of the screw cap finished from the shell illustrated in Figs. 8, 9 and 10.

Figs. 12, 13 and 14 are illustrative of different forms of caps which-may be manufactured by the methods of the present invention.

The most common varieties of skirted closures are made of sheet metal and composition and I have given the subject consideration with the view of producing such closures of wood which would be capable of standing up in usage and at the same time assume a form which is not excessively large and awkward. Because of the strength and formability of sheet metal, screw caps made from sheet metal need be only but slightly larger than the bottle neck with which the cap is to be used and the same is true for composition caps except that more material is necessary to give proper support and strength to the threads of the latter caps. On the other hand, a thin walled tube of wood is relatively fragile and light threads cut from such a tube are even more so. This is because light pieces of wood are relatively weak and wood fibers give a unidirectional characteristic which renders wood capable of resisting shear in one direction better than in any other direction. A screw cap having an integral crown and skirt is desirable, but if such a cap is made of wood either the skirt or the crown must have its thinnest dimension along the grain of the wood and whether the grain runs parallel to the skirt or parallel to the face of the crown, a thin walled skirt or crown is likely to be quite frangible. So also, threads cut from the skirt, particularly if the grain runs parallel to the axis of the helix, are likely to be quite weak. In addition, the fact that the thread on a glass bottle is not always as accurate and regular as a machine cut screw increases the wear and strain on the engaging thread of a cap. It is therefore unsatisfactory to use ordinary wood having annual rings to make skirted screw caps, especially thin walled caps and small caps requiring relatively light screw threads. I have, accordingly, been led to devise the method of the present invention for making a cap having strength characteristics excelling those of the wood from which it is made and which has a smooth and tough thread capable of withstanding wear incident to rubbing engagement with hard'threads andirregular threads such as are often found on glass bottles.

The cap may be fashioned from a blank or disk similar to that illustrated in Fig. 1 which shows a cylindrical disk cut from a round stick or dowel and having parallel opposite faces 10, 11. Though I have illustrated screw caps made from cylindrical blanks it will appear from the following that the exterior shape of the screw cap is entirely optional and that many varieties of forms may be produced. For the purpose of giving a clear disclosure of my invention, I have illustrated in Figs. 1 to 6 inclusive different steps for constructing ,a cap, and in Figs. '7 to 11 inclusive, another, though similar series of steps.

After the blank as shown in Fig. 1, has been cut from the raw wood to the predetermined size necessary for making a cap of a given size and design, the blank, either plain or stained, as desired, is compressed.

In compressing the wooden blank, it is forced down into a tubular die by means of an upper plunger die which forces the blank with great pressure upon a lower die. The blank is of 110 greater girth than the bore of the tubular die and the side walls of the die compress the wood radially inwardly and impart a high finish to the sides of the blank. The upper and lower dies shape and impart a high finish to the faces of the blank. Different designs may be imparted to the top, of the blank, and, as shown in Fig. 2, the edge of the blank may be given a moulded effect as at 12 and left smooth as at 13, or may be given any one of many varieties of designs, as desired.

Since the lateral dimension of the tubular die is less than that of the blank in its natural state, the lateral compression which takes place as the blank enters the flaring mouth of the tubular die tends to straighten the grain of the wood as well as to compact it laterally. The final movement of the upper die as it carries the blank against the lower die results in an axial compression and this axial compression is increased at the center of the blank by causing the dies to depress a recess 14 such as shown in Fig. 2.

While a different procedure will be disclosed in order to insure sufficient toughness for the material of the threads the diameter of the recess 14 is made substantially equal to the root diameter of the threads subsequently to be cut. The lateral and axial compression of the wood results in compacting the fibres thereof and the relatively large pores are closed ordecreased in size to such an extent as to materially increase the strength of the wood and change its character so that a cutting tool leaves a smooth surface.

The next step in the method involves removing the center of the blank. In Figs. 3, 4 and 5 I have illustrated the blank after it has been drilled to remove its center. This blank has a hole 16 which is of a diameter no greater than the diameter of the top of the thread which is subsequently to be cut. The annular area 17 of densified wood remains after the drilling operation and the threads are cut from this area. In the drilling and thread cutting operations the cap may be mounted on a screw cutting machine or on any well known type of turret lathe which is properly equipped for performing these op-' erations.

Figs. 7 to 11 inclusive, show various views of a cap in a process of manufacture similar to that described except that the diameter of the drilled hole 19 is substantially the same as that of the recess 20 which has been created by the compressing operation. Since the thread is cut outside of the area of the recess 20, the material of the thread is apparently of the same density as the material of the shell. This method may be utilized when there is to be more material left in the thread, that is to say, when the thread is to be relatively heavy, but on the other hand, the entire volume of the blank may be more compressed so that the wood in the thread would be sufficiently tough though the thread be of light dimensions.

In addition to placing the wood in good condition for cutting and finishing by the cutting and threading tools, the compressing operation is suitably adapted for shaping the blank into many different forms. The die which bears upon the top of the blank may be cut for embossing suitable identifying, decorative or advertising matter and different shapes are illustratively shown in Figs. 12, 13 and 14.

The recess created by compression in the under side of the cap finishes the outer edge of the skirt and leaves a true circular area for fitting. over the end of a bottle neck. In this particular, as well as in others'resulting from the compression to which the wood has been subjected, uniformity in results are obtained in a cheap and efiicient manner. Any rather tough wood is suitable, but I have obtained excellent results by using well seasoned maple and prefer its use.

When the cap has been produced as the result of the method described it may be suitably colored, if this has not already been done, and a finishing coating of protective enamel will render the cap both waterproof and alcohol-proof. In most cases the finished cap will be provided with a cork pad 21 which lies against the inner surface of the crown.

I claim:-

1. The method of making a wooden screw cap comprising compressing a blank axially while holding it in a tubular die and applying greater pressure over an inside area of a surface of the blank than over the remaining area, removing material from the center of the blank, and cutting a thread in the wall of the hole from which the material has been removed.

2. The method of making a wooden screw cap comprising cutting a piece of wood into a blank or disk, compressing a recess in one side of the blank while supporting the blank in a die. cutting a hole in the blank of less diameter than the recess, and cutting a thread in the wall of the hole.

3. The method of making a closure from a single piece of wood comprising strengthening the wood by compression of the same by the application of force against all of its surfaces, removing a center portion of compressed wood from the interior of the compressed piece of wood while leaving a skirt and crown, and cutting threads in the skirt. Y

4. The method of making a closure from a single piece of wood comprising forcing a blank into a tubular die, compressing the blank between o'pposite dies and within the tubular die, one of which dies has a projection for leaving a recess in one surface of the blank, cutting material from the center of the compressed blank so as to leave a shell open at one side, and cuttgigla thread in the inner wall of the skirt of the s e 5. The method of making a closure from a single piece of wood comprising forcing a blank into a tubular die, compressing the blank between opposite dies and within the tubular die, one of which dies has a projection for leaving a recess in one surface of the blank, drilling a hole of less diameter than the recess, and cutting a thread in the wall of the hole.

6. As an article of manufacture, a bottle cap of compressed wood and consisting of an integral crown and skirt, said skirt forming a cylindrical interior of substantial depth for fitting over the neck of a bottle, said bottle cap having an embossed surface for the exterior of the crown and skirt, and a cut screw thread upon the interior surface of the skirt and integral therewith, all of the wood fibers of the bottle cap being disposed longitudinally of the axis of the skirt and the fibers of the wood in the threaded portion of the skirt being axially compacted to provide dense and strong thread structure.

7. As an article of manufacture, a bottle cap having a crown and skirt and consisting of skirt portion, the outer surface of the cap being embossed and the inner surface of the skirt having cut screw threads for gripping threads when screwed home upon the threaded neck of a. bottle.

JOHN RUTHERFORD, JR. 

